Mypongia brevipes Southcott, 1961

Seeman, Owen D., Beard, Jennifer J., Fan, Qing-Hai & Otto, Jürgen C., 2024, Abrolophus from Australasia, and the mysterious Mypongia (Trombidiformes: Parasitengona: Erythraeidae), Zootaxa 5519 (2), pp. 151-189 : 152-160

publication ID	https://doi.org/ 10.11646/zootaxa.5519.2.1
publication LSID	lsid:zoobank.org:pub:BBED2BAD-1AAE-440B-B13A-0661F309A6BA
DOI	https://doi.org/10.5281/zenodo.13935666
persistent identifier	https://treatment.plazi.org/id/0060C53D-082E-FFB3-3DA0-F94C2FEE4C37
treatment provided by	Plazi
scientific name	Mypongia brevipes Southcott, 1961
status

Treatment

Mypongia brevipes Southcott, 1961 View in CoL

Figures 1–6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6

Diagnosis. Larva. Prodorsal sclerite reduced to an irregular region of smooth soft cuticle around crista metopica; prodorsum with 4 pairs of setae. Dorsum with 18 pairs of setae, mildly hypertrichous C row (six pairs) and D row (four pairs). Coxa I with two pairs of setae; coxa II lacking setae. Gnathosoma lacking proximal setae bs. Palp slender, femur and tibia each at least twice as long as wide, all palp setae smooth and unspecialised; paradont absent. Leg setation reduced, especially genua and tibiae II–III; setal counts, trochanter to tarsus: leg I 2-3/5-8+σ-10+2ϕ+κ–16+duplex+ω+ε; leg II 2-3/4-5+σ+κ-5+2ϕ-13+duplex+ω; leg III 2-3/4–5+σ-5+ϕ-14. Leg setae smooth or sparsely barbed.

Material examined. 4 larvae, as follows. New Zealand : 1 larva, ex kiwifruit, 28 Sep 2000 ( QMB; Q19775 View Materials ) . 1 larva, ex kiwifruit, 3 Jun 2015 (N162334), drawn specimen. 1 larva, ex kiwifruit, 14 Nov 2020 (BISS: 399629, Q180666, 132763QA) [fragments of specimen—idiosoma and one leg, matched but not measured]. South Australia : 1 larva, Belair, 30 May 1990, R.V. Southcott, soil and litter under Euc. camaldulensis. Tx 305, By B. t. on 7 Jun 1990 ( SAM J24237 View Materials ) [poor mount, measured where possible].

Other material examined. South Africa: 1 larva, Potchefstroom, ex moist litter and grass, 28 Apr 1982, D.E. Johnston [ SAM J24239 View Materials ] (identified as an undescribed species of Mypongia ) .

Description (n=3 measured).

Metric data in Table 2 View TABLE 2 .

Dorsum ( Figs 1 View FIGURE 1 , 3A View FIGURE 3 ). Scutum reduced to a lightly sclerotised region poorly defined by limits of prodorsal striation, lacking setae. Crista well-defined, anteriorly and posteriorly capturing trichobothria ASens and PSens, respectively. ASens and PSens slender with few tiny barbs. Prodorsum with 4 pairs of setae, AL setae shortest, scapular (Sc) setae longest; ML, PL intermediate in length; all prodorsal setae slender, with few barbs; epl microphalliform, typical for Trombidiformes . Opisthodorsum with 18 pairs of setae, becoming slightly thicker and longer posteriorly; mid C-row setae irregular in position, other opisthosomal setae in pairs forming rows.

Venter ( Fig. 2 View FIGURE 2 ). Striae between coxae I–II longitudinal; region between coxae II–III with six pairs of setae (excluding 3a), medial striae alternating between regions of transverse and longitudinal; opisthoventer with nine pairs of setae (including ps1-2), striae transverse (arching medially). All setae fine; setae 1a, 1b, 1c, 3b smooth; all other setae with few barbs. Apodemes I–III with narrow anterior margins, posterior margins poorly defined; coxae I-II adjacent, lacking setae in between.

Gnathosoma ( Fig. 3B, C View FIGURE 3 ; 4A, B View FIGURE 4 ). Anterior ventral gnathosoma with four pairs of setae, cs fine, 14–17, as1- 2 small (5–6), as3 slightly longer (7–9) and thicker. Dorsally with small rod-like supra palp-coxal seta ep. Palp elongate, almost linear (i.e. not conspicuously elbowed); palp femur 45–46 long, 20–22 wide; genu 30–31 long, 17– 20 wide; palp tibia with simple odontus, lacking paradont; palp tarsus with seta ul′′ longest, eupathidion ξ slightly shorter, solenidion ω thin. Setal counts femur-tarsus: 2-3-3+claw-5+ω+ξ. Chelicerae hook-like, lacking teeth.

Legs ( Figs 4 C–E View FIGURE 4 , 5–6 View FIGURE 5 View FIGURE 6 ). Leg segmentation formula 7-7-7. All legs shorter than body, legs I and III longest. Leg setation reduced in number, all setae fine and smooth or with few barbs. Genu I with one solenidion σ, lacking microseta κ; genu II with one solenidion σ, with minute microseta κ; genu III with one solenidion σ. Tibia I with two solenidia ϕ and microseta κ in line, decreasing in size distally; tibia II with two solenidia ϕ well-separated from each other, lacking microseta κ; tibia III with one solenidion ϕ. Tarsus I with famulus ε distant from dorsal duplex setae formed by long eupathidion tcξ′ and small fine companion seta z; proral seta p′ fine and densely barbed (perhaps better interpreted as u′′, with p′ absent), eupathidial pξ′′ smooth, long, thin; tarsus II with duplex setae (tcξ′ + z) and long thin proral eupathidion pξ′′; tarsus III with tc′ barbed tactile seta, lacking companion seta z. Claws and empodia claw-like, smooth. Setal formulae, trochanters to tarsi: leg I 2-3/5-8+σ-10+2ϕ+κ-16+duplex+ω+ε; leg II 2-3/4-5+σ+κ-5+2ϕ-13+duplex+ω; leg III 2-3/4-5+σ-5+ϕ-14. Leg setae smooth or sparsely barbed.

Remarks. Southcott (1961) described M. brevipes from a single larva collected from vegetation at Myponga, an elevated locality close to the coastline at the southern end of the Mt Lofty Ranges, South Australia. The holotype was unavailable for study because it is missing from the SAM, but the material from New Zealand matches Southcott (1961) closely ( Table 2 View TABLE 2 ). In addition to the newly collected material from New Zealand, the South Australian Museum held two additional larval Mypongia specimens. The specimen from Belair, South Australia, is partially spoiled, overly flattened and crumpled. The measurements also match the Southcott description well (PSens is somewhat smaller; Table 2 View TABLE 2 ), but there may be an intercoxal seta (apparently asymmetrically expressed) between coxae I-II and two setae on coxae II (asymmetrically expressed). The setae on coxae II could be illusions caused by a fold of soft seta-bearing cuticle. The larval specimen from South Africa is an undescribed species that was collected with an adult Abrolophus species close to A. ripicola ( Tables 1 View TABLE 1 , 2 View TABLE 2 ). In addition to the measurements, particularly the PSens being much longer than ASens ( Table 2 View TABLE 2 ), the crista is punctate and similar to that of nymphal and adult A. ripicola .

Mypongia is a highly distinctive larva. The leg setation is greatly reduced, with the most reductions being on genu II-III and tibia II-III (only 5 tactile setae). As far as we are aware, other larvae of Erythraeidae have 7–9 genual setae and 10–13 tibial setae on leg II. Setal counts are usually similar on leg III, although some exceptions exist (e.g. Monteustium marezensis Haitlinger & Sundic 2015 has 11+ϕ+k on tibia II and 8+ϕ on tibia III). In Southcott’s (1961) classification, the larva of M. brevipes belongs to the Balaustiinae due to its crista and absence of a prodorsal sclerite.